In general, in the case where an originator tries a phone call on a conventional mobile communications network, there is used a method in which a terminating mobile switching center provides a uniform ring-back tone to the originator. However, such a conventional ring-back tone service method is problematic in that the conventional ring-back tone service method provides a uniform tone, so that an originator cannot determine whether an erroneous connection is made or not before the response of a terminator and various ring-back sound services consistent with the characteristics of users cannot be provided. Recently, there was proposed a method of providing various advertising sounds instead of the uniform ring-back tone described above. However, this method is also problematic in that a network provider provides advertising sounds to originators without choice and allows the originators to make calls free of charge for a certain time, an originator cannot determine whether an erroneous connection is made or not before the response of a terminator and various ring-back sound services consistent with the characteristics of users cannot be provided.
In order to solve the above-described problems, the applicant of the present invention proposed a subscriber-based ring-back sound service method that provides originators with specific ring-back sounds registered or selected by subscribers, which is described with reference to FIG. 1 below.
FIG. 1 is a flowchart showing the prior art subscriber-based ring-back sound service method proposed by the applicant of the present invention (see Korean Pat Appl. No. 10-2002-0010006 filed on Feb. 25, 2002).
When an originator calls a subscriber to a service proposed by the patent application and requests a call connection, a corresponding originating Mobile Switching Center (MSC) 31 requests terminating location information from a Home Location Register (HLR) 10 at step S101.
The HRL 10 requests routing information from a terminating MSC 32 in response to the request of step S101 at step S102, and the terminating MSC 32 provides the routing information (Temporary Local Directory Number (TLDN)) to the HLR 10 in response to the request of step S102 at step S103.
The HLR 10 transmits the routing information to the originating MSC 31 in response to the request of step S101 at step S104. Accordingly, the originating MSC 31 requests a trunk (hereinafter referred to as “ISDN User Part (ISUP)”) call connection from the terminating MSC 32 based upon the routing information to establish a call path at step 105.
Thereafter, if it is determined that a terminator is a subscriber to the service of the patent application and the service is activated based upon service establishment information and information for performing routing to an Intellectual Peripheral (IP) 50 provided by the HLR 10 and previously stored in the terminating MSC 32 at the time of registering the location, the terminating MSC 32 requests an ISUP call connection from the IP 50 to establish a trunk call path based upon this routing information and, at this time, provides both a terminating phone number and an originating phone number at step S106. As a result, the call paths are established among the originating MSC 31, the terminating MSC 32 and the IP 50. For reference, the service establishment information and the routing information are included in a location registration response message downloaded from the HRL 10 to the terminating MSC 32, and are provided to the terminating MSC 32.
The IP 50 inquires a ring-back sound code from the IP server 70 based upon the provided terminating and originating phone numbers at step S107, and the IP server 70 searches for the ring-back sound code allocated in connection with the provided terminating and originating phone numbers and transmits the searched ring-back sound code to the IP 50 in response to the inquiry of step S107 at step S108. The IP 50 transmits a ring-back sound corresponding to the received ring-back back sound code, instead of a ring-back tone, to the originator through the established call path at step S109.
Finally, when the terminating subscriber answers the phone while the ring-back sound is being transmitted to the originator, the terminating MSC 32 requests the IP 50 to disconnect the ISUP call connection so that the IP 50 can disconnect the ISUP call connection at step S110, and, at the same tune, allows the originator and the terminating subscriber to make a call through the call path established between the originating MSC 31 and the terminating MSC 32 at step S111.
Meanwhile, in the above-described conventional subscriber-based ring-back sound service method, as the number of subscribers increases, the IP 50 should store a larger number of ring-back sounds. The ring-back sounds may be classified into two types: common ring-back sounds fixedly stored in the IP 50 and individual ring-back sounds recorded, edited and uploaded on the Internet by subscribers. As the ring-back sound service is continuously provided, the number of common ring-back sounds provided by a Content Provider (CP) increases, and the number of individual ring-back sounds increases due to an increased number of subscribers, so that the number of ring-back sounds to be stored must explosively increase. Accordingly, there is an inconvenience, in which the capacity of geometrically distributed IPs should be expanded when the number of ring-back sounds to be stored exceeds the capacity of the IPs, or a problem, in which individual ring-back sounds are not sufficiently serviced because the expansion of capacity of the IPs does not catch up with the increased number of ring-back sounds.
Further, as described above, in the case where an originator tries a phone call in a conventional mobile communications network, there is used a method in which a terminating MSC provides a uniform ring-back tone to the originator. However, such a conventional ring-back tone service method is problematic in that the conventional ring-back tone service method provides a uniform tone, so that an originator cannot determine whether an erroneous connection is made or not before the response of a terminator and various ring-back sound services consistent with the characteristics of users cannot be provided.